In the art of well drilling, it is common practice to run multiple tools, often using conventional setting mechanisms. In cased wells, tool wearing by the casing is typically limited. However, in uncased wells, the borehole walls constitute highly abrasive surfaces that tend to damage the tools, in particular elements that are in contact with the borehole walls when running the tools that are typically folded away during placement operations and/or elements that are deflated such as packer, often made of rubber or other readily abraded materials.
Some types of cover sometimes protect the most sensitive parts of the tools but overall, the tools are left exposed to the aggressive wellbore environment, for example as in U.S. Pat. No. 6,315,041. This raised issues in particular with the development of horizontal or highly deviated wells where the tools may be literally dragged along the borehole. The risks of deteriorating a tool while handling it at surface should also not be neglected.
These issues are of particular concern with a technology consisting of placing a cement plug using a flexible, expandable form made for instance of a stretch fabric formed from steel, rubber, glass fiber, carbon fiber or para-aramid fiber, that holds the cement in place and thus allows rigorously correct placement. Since the mesh is necessarily loose to allow deformation, threads can easily get loose, thereby creating holes through which the cement slurry will escape.
Therefore, it would be desirable to provide some protecting means to tools until their proper placement in the well. It would also be desirable that the means for operating said protecting means be fully compatible with the tool operating means, in particular, does not require any additional power supply.